take the min(sx,sy) when decomposing scale transform to minimise Over…

…flowErrors

src/nanoemoji/paint.py

@@ -282,7 +282,9 @@ def round(self, ndigits: int) -> "PaintLinearGradient":
 
 def _decompose_uniform_transform(transform: Affine2D) -> Tuple[Affine2D, Affine2D]:
     scale, remaining_transform = transform.decompose_scale()
-    s = max(*scale.getscale())
+    # we take the minimum of (sx, sy) to try to minimize the risk of OverflowErrors
+    # when encoding these to F16Dot16
+    s = min(*scale.getscale())
     # most transforms will contain a Y-flip component as result of mapping from SVG to
     # font coordinate space. Here we keep this negative Y sign as part of the uniform
     # transform since it does not affect the circle-ness, and also makes so that the